Research is currently in progress to investigate the behavioral effects of cocaine in humans and to correlate these effects with selected physiological and neurochemical actions of this drug as well as cocaine blood levels. We have developed a behavioral procedure, utilizing spaced tapping, which maintains behavior sensitive to intravenous cocaine and intravenous and oral amphetamine. The time of cocaine effect correlated well with the peak cocaine blood levels measured in our subjects. Mood changes after intravenous cocaine include increases in vigor, friendliness, elation and confusion. Thirty-two mg of cocaine also caused an increase in anxiety. No depression or anger effects were seen. Subjective effects also were highly correlated with cocaine blood levels; euphoric effects were at a maximum until 15-20 minutes when drug was inhaled. The effects of amphetamine and cocaine on plasma cortisol and plasma MHPG differed. Amphetamine decreased both cortisol and MHPG whereas cocaine caused increases in both of these measures. Further work is in progress to clarify these data. BIBLIOGRAPHIC REFERENCES: Fischman, M.W., Schuster, C.R., Krasnegor, N.A., Shick, J.F.E., Resnekov, L., Fennell, W. and Freedman, D.X.; Cardiovascular and subjective effects of intravenous cocaine in humans. Archives of General Psychiatry, 1976, 33, 983-989. Fischman, M.W.; Evaluating the abuse potential of stimulant and depressant drugs in man. In, Predicting Dependence Liability of Stimulant and Depressant Drugs. T. Thompsom and K. Unna (eds.), National Academy of Sciences, 1977, (in press).